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Memory module installation rules and order

Memory modules must be installed in a specific order based on the memory configuration that you implement and the number of processors and memory modules installed in the server.

Supported memory types

For information on the types of memory module supported by this server, see Memory section in Technical Specifications.

Information about optimizing memory performance and configuring memory is available at the Lenovo Press website:

Memory - Lenovo Press

In addition, you can take advantage of a memory configurator, which is available at the following site:

Lenovo Enterprise Solutions Configurator (Memory Configurations)

Specific information about the required installation order of memory modules in your server based on the system configuration and memory mode that you are implementing is shown below.

Memory modules and processors layout​

Figure 1. Memory modules and processors layout (upper processor board (CPU BD))
Memory modules and processors layout (upper processor board (CPU BD))
Figure 2. Memory modules and processors layout (lower processor board (MB))
Memory modules and processors layout (lower processor board (MB))

The memory-channel configuration table below shows the relationship between the processors, memory controllers, memory channels, and memory module slot numbers.

Table 1. Memory slot and channel identification
ProcessorProcessor 0/1/4/5
ControlleriMC3iMC2iMC0iMC1
ChannelCH1CH0CH1CH0CH0CH1CH0CH1
Slot No.0101010110101010
DIMM No.D1D2C1C2B1B2A1A2E2E1F2F1G2G1H2H1
ProcessorProcessor 2/3/6/7
ControlleriMC3iMC2iMC0iMC1
ChannelCH1CH0CH1CH0CH0CH1CH0CH1
Slot No.0101010110101010
DIMM No.M1M2L1L2K1K2J1J2N2N1P2P1R2R1T2T1

Memory module installation guideline​

  • A label on each DIMM identifies the DIMM type. This information is in the format xxxxx nRxxx PC4-xxxxx-xx-xx-xxx. Where n indicates if the DIMM is single-rank (n=1) or dual-rank (n=2).

  • At least one DIMM is required for each processor. Install at least eight DIMMs per processor for good performance.

  • When you replace a DIMM, the server provides automatic DIMM enablement capability without requiring you to use the Setup Utility to enable the new DIMM manually.

  • Independent memory mode installation order
    Independent memory mode provides the highest level of memory performance, but lacks failover protection. The DIMM installation order for independent memory mode varies based on the number of processors and memory modules installed in the server.
  • Memory mirroring mode installation order
    Memory-mirroring mode provides full memory redundancy while reducing the total system memory capacity in half. Memory channels are grouped in pairs with each channel receiving the same data. If a failure occurs, the memory controller switches from the DIMMs on the primary channel to the DIMMs on the backup channel. The DIMM installation order for memory mirroring varies based on the number of processors and DIMMs installed in the server.